Energy-efficient bridge-to-digital converters

This paper presents an overview of energy-efficient analog-to-digital converters (ADCs) specifically intended for the readout of Wheatstone bridge sensors. Apart from achieving good energy-efficiency, such bridge-to-digital converters (BDCs) must achieve low input-referred offset, drift and noise; high gain accuracy, stability and linearity; as well as high immunity to power-supply and common-mode variations. Various BDC architectures are discussed, beginning with traditional designs, in which an instrumentation amplifier is used to drive an ADC, and moving on to more recent work, which attempt to increase energy efficiency and reduce complexity by eliminating the instrumentation amplifier. The performance of these topologies, and in particular their energy-efficiency, will be compared and summarized.